Co-owned U.S. Pat. Nos. 4,477,325 and 4,738,257 disclose soft, conformable, cross-linked skin barrier compositions, and occlusive dressings utilizing such compositions, having both wet and dry tack and having a moisture-absorbing hydrocolloid phase dispersed therein. A variety of other conformable, moisture-absorbing skin barrier materials similarly capable of adhering to the skin even in the presence of moisture have been disclosed in the prior art and are well known in the medical field.
Transparent, stretchable, vapor-permeable, adhesive-coated films are also known in the medical field as disclosed, for example, in U.S. Pat. No. 3,645,835. Such adhesive films have been widely employed in the construction of incise drapes, transparent dressings, burn and wound covers, and the like.
It is a common practice to utilize conventional medical-grade adhesive tape to secure intravenous (IV) tubulature in place at injection sites. Strips of tape are customarily placed over the tubing at the site to hold it against the skin and prevent unintended extraction should pulling forces be applied to such tubing. It has also been known to utilize stretchable, vapor-permeable, adhesive-coated films as protective covers at such injection sites to help retain the IV tubes or catheters in place and, in particular, to protect the sites against contamination and infection.
While such films often provide the desired protective function, the presence of moisture, particularly for a patient experiencing diaphoresis, may weaken the adhesive seals or prevent such seals from occurring in the first instance. Such a problem also frequently occurs in the attachment and/or retention of conventional adhesive tapes, with the result that films or tapes applied to help hold an IV tube or catheter in place may fail to perform the intended immobilization functions and, at least in some cases, place patients at risk.
We have made attempts to utilize skin-barrier pads as the means for holding IV tubes in place. While such pads may be superior to adhesive tapes and films because of their wet tack and moisture-absorbing capabilities, they are generally opaque or non-transparent, making inspection of the injection sites to ascertain bleeding, phlebitis, or other complications difficult or impossible without pad removal. Such pad removal and replacement is time-consuming, expensive, and increases the risks of site contamination.
Therefore, an important aspect of this invention lies in providing a site-revealing, moisture-absorbing, adhesive dressing that is particularly suitable as a protective cover for IV injection sites and overcomes the aforementioned shortcomings and disadvantages of prior products and procedures. Specifically, a main aspect of this invention lies in providing a dressing that is stretchable and may therefore be placed over an injection site to conform well with the contour of an IV tube or catheter and surrounding areas of skin, that adheres well to the skin and to the IV tube or catheter, that absorbs moisture from the skin about the injection site, that releases such moisture to atmosphere at controlled rates and that is also permeable to oxygen and carbon dioxide, and that permits visual inspection of the injection site while the dressing is in place.
Briefly, the adhesive dressing of this invention takes the form of a conformable pad having a thin base layer of stretchable, moisture-absorbing skin barrier material having both wet and dry tack and having a site-inspection opening extending therethrough, a transparent cover layer composed of a thin, stretchable polymeric film that is non-permeable to liquid water but that has both gas and moisture vapor permeability, such cover layer extending over the base layer and its opening and having its underside coated with a clear layer of gas and vapor permeable pressure-sensitive adhesive. Since both the cover layer and its adhesive coating are transparent, the dressing may be readily oriented and applied so that an injection site is visible through the opening in the relatively opaque base layer and, because of its stretchability, the portion of the cover layer spanning that opening will readily conform and adhere to the tubulature in the area of the injection site. Since the cover layer is imperforate and serves as a bacterial barrier, it effectively protects the injection site and the area of skin covered by the dressing from contamination. At the same time, the gas and vapor permeable cover layer is "breathable" and therefore permits respiration through the dressing. Adherence of the dressing is assured because of the wet tack capabilities of the base layer and because the skin barrier material from which the base layer is formed is capable of absorbing moisture. Thus, the base layer absorbs moisture in liquid form (i.e., perspiration) and the cover layer then relieves the base layer of its moisture content by transmitting such moisture in vapor form to atmosphere.
To serve effectively as a vapor-transmitting dressing, the cover layer and its adhesive layer should have water vapor transmission characteristics of at least 300 grams per square meter over 24 hours at 40.degree. C. and at 80% relative humidity. The thickness of the base layer should fall within the general range of about 0.25 to 0.50 millimeters (10 to 20 mils) and the thin, stretchable cover layer should have a thickness within the range of about 0.025 to 0.050 millimeters (1 to 2 mils). The size of the dressing may vary according to needs but, where used as an IV dressing, the planar measurement in any given direction should fall within the range of about 5 to 10 centimeters (2 to 4 inches).
The underside of the dressing is backed by removable backing means in the form of a pair of release sheets, each sheet being folded along a transverse fold line with the fold lines of the two sheets extending alongside each other across the opening in the base layer. The fold lines provide each release sheet with a tab portion that may be gripped by a user to peel the release sheets away from the dressing and thereby facilitate application of the dressing over and about an injection site.